Answer:
  ω₂=1.20
Explanation:
Given that
mass of the turn table ,M= 15 kg
mass of the ice ,m= 9 kg
radius ,r= 25 cm
Initial angular speed ,ω₁ = 0.75 rad/s
Initial mass moment of inertia 



Final mass moment of inertia



Lets take final speed of the turn table after ice evaporated =ω₂ rad/s
Now by conservation angular momentum 
I₁ ω₁ =ω₂ I₂

ω₂=1.20
 
        
             
        
        
        
Answer:
 24.8m/s
Explanation:
Given data
m1= 10kg
u1=25m/s
m2=17kg
u2=16m/s
v1=10m/s
v2=??
Applying the conservation of linear momentum
m1u1+m2u2=m1v1+m2v2
substitute
10*25+17*16=10*10+17*v2
250+272=100+17v2
522=100+17v2
522-100=17v2
422=17v2
Divide both sides by 17
v2= 422/17
v2= 24.8 m/s
Hence the velocity of the red cart is 24.8m/s in the opposite direction of the blue cart
 
        
             
        
        
        
Answer:
D. 100 cm
Explanation:
The speed of a wave is the wavelength times the frequency.
v = λf
Wave A and B have the same speed, so:
λf = λf
(50 cm) (7000 Hz) = λ (3500 Hz)
λ = 100 cm
 
        
             
        
        
        
It be desirable to use an energy resource that does not produce greenhouse gases because it contribute to climate change
.
Option C
<u>Explanation:</u>
Greenhouse gases are the toxic gases that contribute to the "greenhouse effect". Greenhouse gases have the ability to absorb and emit some of the outgoing energy that is radiated by the Earth's surface, eventually causing the heat to get accumulated in the "lower atmosphere". It is always beneficial to use Renewable Energy sources such as Wind, solar and water which gives no harm to the environment and climate with no greenhouse gas emissions.  
<u>For example:</u> If we have to generate electricity, there will be no greenhouse gas production at the beginning and a very less amount of production at the entire life cycle.